1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member including a cylindrical body having an outer circumferential surface formed with a photosensitive member, and a method of manufacturing the same.
2. Description of the Related Art
Various types of electrophotographic photosensitive members are known, and the common type is in shape of a drum. The drum-shaped electrophotographic photosensitive member includes a cylindrical body having a surface formed with a desired layer such as a photoconductive layer made of amorphous silicon (hereinafter referred to as “a-Si”). Meanwhile, various types of methods for forming a-Si photoconductive layer on a cylindrical body are known. Among them, plasma CVD method is now being put into practical use. In the plasma CVD method, DC voltage, high frequency wave, or microwave is supplied to generate glow discharge for decomposing material gas, so that deposited film is formed on a cylindrical body.
In manufacturing an electrophotographic photosensitive member by such plasma CVD method, a glow discharge plasma CVD device 9 as shown in FIG. 11 is used (refer to JP-A-2002-004050, for example).
The illustrated glow discharge plasma CVD device 9 forms a-Si film, utilizing glow discharge plasma, on a cylindrical conductive body 91 positioned at a substantially central portion of a cylindrical vacuum vessel 90. In the glow discharge plasma CVD device 9, the conductive body 91 supported by a supporting body 92 via a ring 93 serves as a ground electrode. These components are concentrically surrounded by a cylindrical metal electrode 94 which has a hollow portion and serves as an electrode for applying high frequency power. The metal electrode 94 is provided with gas inlet ports 95 for introducing material gas for film forming. The material gas introduced from the gas inlet ports 95 is sprayed toward the conductive body 91 through gas outlet ports 94a provided at the inner circumferential surface of the metal electrode 94. A high frequency power source 96 applies high frequency power across the metal electrode 94 and the conductive body 91 to generate glow discharge. In the supporting body 92, a heating means 97 such as nichrome wire and a cartridge heater is provided for heating the conductive body 91 up to a desired temperature. The supporting body 92 and the conductive body 91 are rotated together by a rotation means 98 including a rotation motor 98a. 
In forming a-Si film on the conductive body 91, material gas of a predetermined amount and gas ratio is introduced from the gas inlet ports 95 into the space between the metal electrode 94 and the conductive body 91 through the gas outlet ports 94a. Meanwhile, gas pressure in the vacuum vessel 90 is set to a predetermined amount by controlling discharge of gas from a gas discharge port 99 using a vacuum pump (not shown). Then, high frequency power is applied across the metal electrode 94 and the conductive body 91 by the high frequency power source 96, so that glow discharge plasma is generated across the metal electrode 94 and the conductive body 91 to decompose the material gas, whereby a-Si film is formed on the conductive body 91 set at a predetermined temperature. In film forming, since the conductive body 91 is rotated together with the supporting body 92 by the rotation means 98, the film is formed to have uniform thickness and property in the circumferential direction of the conductive body 91.
When forming a desired film on the conductive body 91 using the plasma CVD device 9, in order to improve the productivity, for example, as shown in FIG. 12, a plurality of conductive bodies 91 are supported by the supporting body 92 to be incorporated in the plasma CVD device 9, and film forming is performed simultaneously to the plurality of conductive bodies 91.
However, since the adjacent conductive bodies 91 contact each other at end surfaces 91A, gas components existing around the conductive bodies 91 are prevented from contacting the end surfaces 91A. Thus, in forming film on such conductive bodies 91, though the film is formed on the outer circumferential surface of the conductive bodies 91, deposited species is not properly attached to the end surfaces 91A. The deposited species failed to be attached to the end surfaces 91A becomes powdered material which may be attached to the outer circumferential surface of the conductive bodies 91 and exist as fine projections.
Such fine projections cause black spots which lead to image degradation in images formed by an image forming apparatus incorporating the electrophotographic photosensitive member. Therefore, the electrophotographic photosensitive member formed with fine projections must be disposed of as defective goods, which reduces the yield and thus prevents cost reduction, so that demand for lower price cannot be met.
Further, when the end surfaces 91A are not formed with deposited film, adhesion of the film is deteriorated at the end portions of the adjacent conductive bodies 91. Thus, when removing the conductive bodies 91 from the supporting body 92 after film forming, the film may peel off from the end portions of the conductive bodies 91. Such peeling off of the film from the end portions also reduces the yield.